US20110103993A1 - Gear wheel with profile capable of meshing with semi-encapsulation in a geared hydraulic apparatus - Google Patents

Gear wheel with profile capable of meshing with semi-encapsulation in a geared hydraulic apparatus Download PDF

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Publication number
US20110103993A1
US20110103993A1 US12/914,780 US91478010A US2011103993A1 US 20110103993 A1 US20110103993 A1 US 20110103993A1 US 91478010 A US91478010 A US 91478010A US 2011103993 A1 US2011103993 A1 US 2011103993A1
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United States
Prior art keywords
gear wheel
profile
teeth
tooth
height
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Abandoned
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US12/914,780
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English (en)
Inventor
Mario Antonio Morselli
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Settima Meccanica Srl
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Settima Meccanica Srl
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Assigned to MORSELLI, MARIO ANTONIO, SETTIMA MECCANICA S.R.L. reassignment MORSELLI, MARIO ANTONIO ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MORSELLI, MARIO ANTONIO
Publication of US20110103993A1 publication Critical patent/US20110103993A1/en
Priority to US14/287,527 priority Critical patent/US9404366B2/en
Assigned to SETTIMA MECCANICA S.R.L. reassignment SETTIMA MECCANICA S.R.L. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: MORSELLI, MARIO ANTONIO, SETTIMA MECCANICA S.R.L.
Abandoned legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2/00—Rotary-piston machines or pumps
    • F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C2/082—Details specially related to intermeshing engagement type machines or pumps
    • F04C2/084—Toothed wheels
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C2/00—Rotary-piston machines or pumps
    • F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
    • F04C2/12—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
    • F04C2/14—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons

Definitions

  • the present invention refers to a gear wheel, of the type having a profile capable of meshing with semi-encapsulation in a geared hydraulic apparatus.
  • Typical examples of geared hydraulic apparatus in which the gear wheels of the present invention, and to which specific reference shall be made hereinafter, find application are rotary positive displacement pumps, but the gear wheels of the present invention may also analogously be applied to hydraulic geared motors, which are thus deemed included within the scope of protection of the present invention.
  • Rotary positive displacement pumps are generally made up of two gear wheels, in most cases of the straight cut gears, one of which, called driver, is connected to a driving shaft and rotates the other wheel, called driven.
  • ripple noise an indirect operating noise, known as ripple noise, linked to the flow rate pulsation and therefore pressure pulsation in the user circuit.
  • the oscillations in the fluid flow rate generate a pulsating wave which, via the fluid itself, is transmitted to the surrounding atmosphere and, in particular, to the walls of the pump, to the piping and to the delivery pipes.
  • the induced noise may also reach unpredictable levels in the case where the aforesaid members resonate with the oscillation or ripple frequency.
  • the ripple is due to the discontinuity in the variation of said volume with respect to time, or, rather, with respect to the reciprocal angular position of the rotors.
  • the fluid trapped between the teeth is, at least in part, “discharged”, that is, evacuated, via suitable outlets or pockets or ducts provided on the faces of the lateral abutment means, otherwise known as supports or bushes, of the gear wheels, that is, on the walls which face the flat lateral gear wheel ends, and which make it possible to discharge (or suction) the encapsulated volume of fluid towards the appropriate, respectively high or low pressure, port or gate.
  • the teeth types developed by the present inventor do not have a by-pass between intake and delivery of the pump, they have minimum pulsation of the fluid and a notable quietness of meshing.
  • the behaviour of the gear wheels of according to patent application WO 2008/111017 of the same applicants is such that an area for the entrapment or encapsulation of the fluid which gradually, during the rotational movement of the wheels, is reduced up to being substantially cancelled when the head of a tooth of a gear wheel touches the bottom of a tooth of another wheel, is formed between the teeth of the two wheels which mesh.
  • Such behaviour shall be referred to as “semi-encapsulation”.
  • this series of profiles identified specifically has the advantage of high reliability of use, which makes it particularly advantageous in case of use in the positive displacement pumps for high pressures.
  • the proportion of teeth which is higher in the previously known solutions allows obtaining a considerably improved performance.
  • the invention has the object of a gear wheel with a plurality of teeth capable of meshing with the teeth of another corresponding gear wheel, the profile of each tooth of the gear wheel, in transverse section, being defined in the claims that follow.
  • the profile of at least one tooth of one of the two rotors is defined by a spline function passing through a plurality of nodal points having pre-established coordinates, with a tolerance of ⁇ 1/15, more preferably of ⁇ 1/20, and even more preferably ⁇ 1/30 of the height of the tooth of the gear wheel on the theoretical profile defined by the plurality of preferred nodal points.
  • the nodal points are defined by a pair of values ⁇ X′, Y′ ⁇ expressed in a system of cartesian coordinates having origin in the centre of the pitch circle of the gear wheel.
  • the origin of the system of coordinates x,y is the line of the rotational axis of the wheel of a plane perpendicular to the axis itself, which is coincident with the centre of the pitch circle of the gear wheel itself.
  • spline function generally refers to any spline function which does not introduce errors, or a smoothing spline with a smoothing parameter sufficiently small not to introduce considerable errors with respect to the nodal points.
  • the spline function used is a cubic natural spline function, i.e. an interpolation natural spline function of the third degree.
  • the gear wheels are advantageously helical, and the face contact of the helical teeth is comprised between 0.4 and 1.2, preferably between 0.5 and 1.2, more preferably between 0.6 and 1.2, more preferably between 0.7 and 1.1, more preferably between 0.8 and 1.1, and even more preferably between 0.9 and 1.
  • the face contact of the helical teeth is equal or close to one.
  • a gear wheel according to the present invention has a ratio between dimensions of height and pitch circle comprised between 0.5 and 2, preferably between 0.6 and 1.8, more preferably between 0.65 and 1.5, and even more preferably between 0.7 and 1.25.
  • the ratio between dimensions of height and pitch circle is close to one.
  • the present invention also has the object of a geared hydraulic apparatus comprising a pair of meshing gear wheels having teeth profile of the previously described type.
  • a geared hydraulic apparatus comprising a pair of meshing gear wheels having teeth profile of the previously described type.
  • such hydraulic apparatus may be a hydraulic pump or a hydraulic motor.
  • a gear wheel 10 according to the present invention (illustrated only partly in the FIGURE) is intended for meshing with another corresponding gear wheel (not illustrated) for the use of a rotary positive displacement pump, preferably of the type for high operating pressures, where the pressure differential between intake and delivery are greater than a few tens of bars, more particularly greater than about 50 bars, and even more particularly greater than about 80-100 bar.
  • the gear wheel 10 comprises a plurality of teeth 11 with a height H and a profile suitable for meshing with semi-encapsulation with the teeth of the other corresponding gear wheel.
  • the profile of the teeth 11 is not describable as a succession of simple geometrical curves, but it may be defined by a cubic natural spline function (even though it is possible, according to the previously indicated terms, to use other spline functions or smoothing spline) passing through a plurality of nodal points 12 defined by a pair of values expressed in a system of cartesian coordinates having origin in the centre of the pitch circle 13 of the gear wheel 10 .
  • the resulting profiles shall be conjugated, if not exactly from an analytical point of view, at least from a practical point of view, and i.e. the profiles must be capable of meshing correctly in the actual use in the hydraulic apparatus subject of the present invention.
  • the profiles must be capable of meshing correctly in the actual use in the hydraulic apparatus subject of the present invention.
  • the single FIGURE shows a comparison between the profile of the tooth 11 of a gear wheel obtained according to the invention, and the profile of a tooth D of the prior art, drawn in a dash and dot line, designed according to the “non encapsulation” concept. It is immediately observable that the tooth 11 is considerably higher than the tooth D of the prior art, and it is thus understandable how a gear wheel with teeth 11 obtained according to the “semi-encapsulation” principle of the present invention leads to higher positive displacement performance or the gear wheels obtained according to the “non encapsulation” principle, at least due to the fact that a higher number of teeth may be employed considering the same capacity and overall dimension.
  • gear wheels of the present invention having a different number of teeth.
  • a gear wheel having a number of teeth equivalent to seven has a theoretical profile of the tooth defined by a cubic natural spline function (which may be replaced by another spline function or smoothing spline if required) passing through a plurality of nodal points defined by a pair of values ⁇ X′,Y′ ⁇ expressed in a system of cartesian coordinates having origin in the centre O of the pitch circle P of the gear wheel.
  • the coordinates of the nodal points are similar to the pairs of values ⁇ X,Y ⁇ of the list reproduced in the following table 1.
  • a gear wheel having a number of teeth equivalent to eight has a theoretical profile of the tooth defined by a cubic natural spline function (which may be replaced by another spline function or smoothing spline if required) passing through a plurality of nodal points defined by a pair of values ⁇ X′,Y′ ⁇ expressed in a system of cartesian coordinates having origin in the centre O of the pitch circle P of the gear wheel.
  • the coordinates of the nodal points are similar to the pairs of values ⁇ X,Y ⁇ of the list reproduced in the following table 2.
  • a gear wheel having a number of teeth equivalent to nine has a theoretical profile of the tooth defined by a cubic natural spline function (which may be replaced by another spline function or smoothing spline if required) passing through a plurality of nodal points defined by a pair of values ⁇ X′,Y′ ⁇ expressed in a system of cartesian coordinates having origin in the centre O of the pitch circle P of the gear wheel.
  • the coordinates of the nodal points are similar to the pairs of values ⁇ X,Y ⁇ of the list reproduced in the following table 3.
  • a gear wheel having a number of teeth equivalent to ten has a theoretical profile of the tooth defined by a cubic natural spline function (which may be replaced by another spline function or smoothing spline if required) passing through a plurality of nodal points defined by a pair of values ⁇ X′,Y′ ⁇ expressed in a system of cartesian coordinates having origin in the centre O of the pitch circle P of the gear wheel.
  • the coordinates of the nodal points are similar to the pairs of values ⁇ X,Y ⁇ of the list reproduced in the following table 4.
  • the production (and design) tolerance of the gear wheels must be such to guarantee that the profile of the cut teeth is comprised in a band of tolerance of ⁇ 1/15, more preferably ⁇ 1/20, and even more preferably ⁇ 1/30 of the height of the tooth of the gear wheel.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Rotary Pumps (AREA)
  • Lubricants (AREA)
US12/914,780 2009-10-30 2010-10-28 Gear wheel with profile capable of meshing with semi-encapsulation in a geared hydraulic apparatus Abandoned US20110103993A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US14/287,527 US9404366B2 (en) 2009-10-30 2014-05-27 Gear wheel with profile capable of meshing with semi-encapsulation in a geared hydraulic apparatus

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITBO2009A000714 2009-10-30
ITBO2009A000714A IT1398817B1 (it) 2009-10-30 2009-10-30 Ruota dentata con profilo atto ad ingranare con semi-incapsulamento in un'apparecchiatura idraulica ad ingranaggi

Related Child Applications (1)

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US14/287,527 Continuation-In-Part US9404366B2 (en) 2009-10-30 2014-05-27 Gear wheel with profile capable of meshing with semi-encapsulation in a geared hydraulic apparatus

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US20110103993A1 true US20110103993A1 (en) 2011-05-05

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US12/914,780 Abandoned US20110103993A1 (en) 2009-10-30 2010-10-28 Gear wheel with profile capable of meshing with semi-encapsulation in a geared hydraulic apparatus

Country Status (6)

Country Link
US (1) US20110103993A1 (fr)
EP (1) EP2317144A3 (fr)
CN (1) CN102052447B (fr)
BR (1) BRPI1003887A2 (fr)
IT (1) IT1398817B1 (fr)
TW (1) TW201124653A (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140271314A1 (en) * 2009-10-30 2014-09-18 Settima Meccanica S.R.L. Gear Wheel with Profile Capable of Meshing with Semi-Encapsulation in a Geared Hydraulic Apparatus

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102322419B (zh) * 2011-09-30 2016-01-20 浙江奥威特液压机械有限公司 螺杆泵
WO2017100517A1 (fr) * 2015-12-11 2017-06-15 Gear Innovations Llc Engrenages conjugués avec contact de flanc de dent continu
CN106015516B (zh) * 2016-05-24 2018-06-12 北京航空航天大学 一种基于b样条啮合线的内啮合齿轮齿形设计方法
DE102017221736B4 (de) 2017-12-03 2021-11-25 Audi Ag Verfahren zur Akustikbeeinflussung von Zahnrädern

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2159744A (en) * 1936-08-26 1939-05-23 Brown & Sharpe Mfg Gear pump
US3164099A (en) * 1961-08-09 1965-01-05 Iyoi Hitosi Toothed profiles of rotors of gear pump
US3209611A (en) * 1961-05-02 1965-10-05 Iyoi Hitosi Teeth profiles of rotors for gear pumps of rotary type
US6769891B2 (en) * 2002-06-12 2004-08-03 Mario Antonio Morselli Rotary positive-displacement pump with meshing gear wheels without encapsulation, and gear wheel for such a positive-displacement pump
US20100104463A1 (en) * 2007-03-14 2010-04-29 Settima Meccanica S.R.L. Geared hydraulic apparatus

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2304155B (en) 1994-07-07 1998-08-19 Brown David Hydraulics Ltd Helical gear pump or motor
IT1283389B1 (it) * 1995-03-10 1998-04-17 Stem Numerical Engineering Srl Profili per rotori di compressori roots
EP1195541A4 (fr) * 1999-06-14 2004-05-19 Wei Xiong Engrenage et appareil pour fluide a double engrenage
ITBO20000119A1 (it) 2000-03-08 2001-09-10 Mario Antonio Morselli Pompa volumetrica rotativa a rotori elicoidali .

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2159744A (en) * 1936-08-26 1939-05-23 Brown & Sharpe Mfg Gear pump
US3209611A (en) * 1961-05-02 1965-10-05 Iyoi Hitosi Teeth profiles of rotors for gear pumps of rotary type
US3164099A (en) * 1961-08-09 1965-01-05 Iyoi Hitosi Toothed profiles of rotors of gear pump
US6769891B2 (en) * 2002-06-12 2004-08-03 Mario Antonio Morselli Rotary positive-displacement pump with meshing gear wheels without encapsulation, and gear wheel for such a positive-displacement pump
US20100104463A1 (en) * 2007-03-14 2010-04-29 Settima Meccanica S.R.L. Geared hydraulic apparatus

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Internet Article entitled "Module for Cubic Splines" by John H. Mathews. Internet Location: math.fullerton.edu/mathews/n2003/CubicSplinesMod.html *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140271314A1 (en) * 2009-10-30 2014-09-18 Settima Meccanica S.R.L. Gear Wheel with Profile Capable of Meshing with Semi-Encapsulation in a Geared Hydraulic Apparatus
US9404366B2 (en) * 2009-10-30 2016-08-02 Settima Meccanica S.R.L. Gear wheel with profile capable of meshing with semi-encapsulation in a geared hydraulic apparatus

Also Published As

Publication number Publication date
ITBO20090714A1 (it) 2011-04-30
BRPI1003887A2 (pt) 2012-06-12
CN102052447B (zh) 2017-04-12
TW201124653A (en) 2011-07-16
EP2317144A2 (fr) 2011-05-04
EP2317144A3 (fr) 2012-12-26
CN102052447A (zh) 2011-05-11
IT1398817B1 (it) 2013-03-21

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Owner name: SETTIMA MECCANICA S.R.L., ITALY

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Effective date: 20141106